Pharmaceutical drug products must be manufactured into dosage forms in order to be marketed for use. Conventional dosage forms typically involve a mixture of active pharmaceutical ingredients and inactive components (excipients), along with other non-reusable materials such as a capsule shell. Categories of dosage forms include liquid dosage forms (e.g., solutions, syrups, elixirs, suspensions and emulsions), solid dosage forms (e.g., tablets, capsules, caplets and gel-caps), and semi-solid dosage form (e.g., ointments and suppositories), among which solid dosage forms are more advantages to administer drugs in systemic effect through oral route.
Tablets are most commonly used solid dosage forms, which shows more benefits in terms of manufacturing, packaging and shipping, and easy to identify and swallow. After being administered into a living organism, a tablet undergoes interplay with the body in exerting pharmaceutical effects. The active pharmaceutical ingredient must be released from the tablet before being absorbed into the blood circulation. The pharmaceutical ingredient then disperses, disintegrates or dissolves throughout the fluids and tissues of the body. During drug absorption, disposition, metabolism, and elimination process, dosage forms play a critical role in determining the release profile and bioavailability of the drugs. Therefore, there is a continuing needs for developing dosage forms that provides controlled drug delivery systems, which may offer desired drug plasma levels, reduced side effects as well as improved patient compliance.